Hi all, I have a cactus my father gave me around 7 years ago. My dad passed away about 5 years ago and I've had the cactus ever since and really want to keep it because it has a lot of meaning. He gave me two of them but the other one died about 6 months ago and this last one appears to now be having the same problem the other one did that died. I've added some photos of what it looks like now. The cactus is about 20 inches high and I usually water it with a glass of water about once a month. I live in an apartment that's usually around 75 degrees and there's not much sunlight at all. The cactus seems to be developing some rotting of some sort if I had to guess but I don't know much about cacti. It looks like it's coming from the bottom and almost working it's way up but I'm not sure. The top 6 inches or so of the cactus appear fine. I've done a little YouTubing and I'm wondering if the roots are rooting and if I should attempt to cut it and re-pot it. I've never done that though and don't want to lose the cactus so I was hoping someone could help me out. Could someone please tell me what they think and provide some recommendations? I would greatly appreciate it and can provide private contact info if needed. Thanks so much!